Implantable medical devices may be used to deliver neurostimulation therapy to patients to treat a variety of symptoms or conditions such as chronic pain, tremor, Parkinson's disease, epilepsy, incontinence, or gastroparesis. An implantable medical device may deliver neurostimulation therapy via leads that include electrodes located proximate to the spinal cord, pelvic nerves, or stomach, or within the brain of a patient. In general, the implantable medical device delivers neurostimulation therapy in the form of electrical pulses.
A clinician may select values for a number of programmable parameters in order to define the neurostimulation therapy to be delivered to a patient. For example, the clinician may select a voltage or current amplitude and pulse width for a stimulation waveform to be delivered to the patient, as well as a rate at which the pulses are to be delivered to the patient. The clinician may also select as parameters particular electrodes within an electrode set to be used to deliver the pulses, and the polarities of the selected electrodes. A group of parameter values may be referred to as a program in the sense that they drive the neurostimulation therapy to be delivered to the patient.
The process of selecting values for the parameters that provide adequate results can be time consuming, and may require a great deal of trial and error before a “best” program, e.g., a program that is better in terms of clinic efficacy versus side effects experienced than other programs tested, is discovered. The clinician may be required to make notations describing a number of programs and feedback received from the patient regarding the perceived efficacy of each program. The clinician may then select the “best” program based on the notations.
Even after this often-lengthy process, the selected program may be inadequate to alleviate all of the symptoms of the patient. The symptoms may vary throughout the day or depending on the position of the patient, e.g., standing, sitting, lying down, etc. Additionally, the symptoms may change over a longer period of time such that the selected program is no longer effective, often requiring the clinician to start the program selection process anew.